A VENT ASSEMBLY AND A METHOD FOR HEATING AIR ENTERING A ROOM THROUGH A WALL VENT

Abstract: A vent assembly (1) for mounting in a wall vent (2) of an outside wall (3) of a room of a house comprises a housing (17) which is located in a shaft liner (18) in the wall vent (2). A main duct (20) extends through the housing (17) from a main duct inlet (21) to a main duct outlet (23), and a heat exchanger (25) located in the main duct (20) heats air passing through the main duct (20) for delivery to a room. An inlet cover (105) with a louvred air inlet (106) accommodates air from outside into the main duct (20), while an outlet cover (78) with a louvred air outlet (88) delivers the heated air from the main duct (20) into the room. A secondary heat exchanger (91) is located in a secondary duct (90) for heating air for recirculating into the room.

Description: "A vent assembly and a method for heating air entering a room through a wall vent" The present invention relates to a vent assembly for locating in a wall vent and to a method for heating air entering a room through a wall vent. The invention also relates to a wall having a wall vent and comprising the vent assembly located in the wall vent. Local authority building regulations require a wall vent to be provided in a wall of certain rooms of a house or other buildings. In particular, it is a requirement that a wall vent should be provided in a wall of a room in which an oil fired or gas fired boiler is installed, and also, in a room in which a gas fire is installed. In general, it is a requirement that such vents be installed in an outer wall of the building, and generally, such vents are provided by a horizontal shaft extending through the outer wall from an outer surface to an inner or room surface of the wall. The shaft terminates in the outer surface in a shaft inlet and terminates in the inner surface of the wall in a shaft outlet for delivering air into the room. Since the function of such wall vents is to deliver air from outside into the room, unfortunately, such vents, in general, create a draught of cold air in the room, particularly in winter. Where the vent is provided relatively high up in the wall, a downward draught is caused in the room which can cause considerable discomfort to a person standing or sitting beneath the wall vent, and where such a vent is provided relatively low down in the wall, a draught is created which can cause considerable discomfort to an individual's feet and/or legs standing or sitting in the room near the wall vent. There is therefore a need for a vent assembly for fitting in or adjacent the wall vent which minimises cold draughts in a room of a building, and also can provide heating for the room. Additionally, there is a need for a method for minimising cold draughts in a room, and for heating air entering a room through a wall vent. There is also a need for a wall having a wall vent extending therethrough and the vent assembly located therein. The present invention is directed towards providing such a vent assembly, a method and a wall. According to the invention there is provided a vent assembly for mounting in a wall vent extending through a wall of a room, the wall vent being of the type having a vent shaft extending through the wall from a shaft inlet formed in the outer surface of the wall to a shaft outlet formed in the inner surface of the wall, the vent assembly being of the type comprising an elongated main duct for mounting in the vent shaft for delivering air through the vent shaft into the room, the main duct extending between a main duct inlet at an upstream end for receiving the air, and a main duct outlet at a downstream end through which the air is delivered to the room, wherein a main heating means for heating air flowing through the main duct is provided. The advantages of the invention are many. The main advantage of the invention is achieved by virtue of the fact that air on being drawn into a room, by, for example, the draught on an oil fired or gas fired central heating, or indeed, any other heating appliance which causes a draught through the room is heated in the vent assembly. Thus, the air entering the room is heated thus avoiding any danger of cold air entering the room, and irritant cold draughts being set up in the room. Additionally, a further advantage of the invention is that it heats air entering the room from outside, and provided the heat capacity of the main heat exchanger is such the vent assembly may provide all the heat required for heating a room. Where the vent assembly is provided with a secondary heat exchanger, additional heating is provided and air for recirculation can be heated. A further advantage of the invention is achieved in cases where the main duct inclines upwardly from the main duct inlet to the main duct outlet. In this way, even where a draught is not provided in the room by a central heating boiler or other devices, natural convection of air in the duct causes heated air to be passed through the main duct and into the room. Preferably, the main heating means is located in the main duct for maximising heat transfer to the air passing through the main duct. Advantageously, the main heating means extends transversely of the main duct, and preferably, the main heating means extends completely across the main duct so that substantially all the air passing through the main duct passes through the main heating means. It is preferable that the main duct should rise from the main duct inlet to the main duct outlet to facilitate natural convection of heated air through the main duct. Preferably, the main duct inlet is below the level of the main duct outlet. Ideally, the main heating means extends in a plane substantially horizontally. Preferably, the main heating means is located at a level below the main duct outlet and at a level above the main duct inlet for maximising natural convection of heated air through the main duct. It is desirable that an intermediate portion of the main duct intermediate the upstream end and the downstream end extends in a substantially vertical direction, the main heating means being located in the vertically extending intermediate portion of the main duct. This enhances natural convection of air through the main duct. In one embodiment of the invention, the main heating means comprises a main water heat exchanger. Preferably, the main water heat exchanger comprises a radiator comprising a plurality of spaced apart elongated water carrying heat exchange tubes defining respective outer heat exchange surfaces for transferring heat from the water to air. Advantageously, a plurality of spaced apart heat exchange fins extend from the heat exchange tubes of the main heat exchanger, the heat exchange fins engaging the heat exchange tubes with heat conducting engagement for transferring heat to the air. In one aspect of the invention, a secondary duct is provided extending from a secondary duct outlet adjacent the main duct outlet to a secondary duct inlet for receiving air from the room for delivering the air through the secondary duct and through the secondary duct outlet for return to the room, and preferably, a secondary heating means is provided for heating air flowing through the secondary duct, for facilitating recirculation of air through the room, and heating of the recirculated air. Preferably, the secondary heating means is located in the secondary duct for maximising heat transfer to the air passing through the secondary duct. Ideally, the secondary heating means extends transversely across the secondary duct. Preferably, the secondary heating means extends completely across the secondary duct. It is desirable that the secondary duct should rise from the secondary duct inlet towards the secondary duct outlet, for facilitating natural convection of heated air through the secondary duct. Advantageously, the secondary duct outlet is above the level of the secondary duct inlet. Preferably, the secondary heating means is located below the secondary duct outlet and above the secondary duct inlet, for maximising natural convection of heated air through the secondary duct. In one aspect of the invention, the secondary heating means comprises a secondary water heat exchanger. Preferably, the secondary water heat exchanger comprises a radiator comprising a plurality of spaced apart elongated water carrying heat exchange tubes defining respective outer heat exchange surfaces for transferring heat from the water to air. Advantageously, a plurality of spaced apart heat exchange fins extend from the heat exchange tubes of the secondary heat exchanger, the heat exchange fins engaging the heat exchange tubes with heat conducting engagement for transferring heat to the air. In one embodiment of the invention, an accommodating means is provided for accommodating a flow and return pipe for connection to each heat exchanger. Preferably, a valve means is provided for controlling the supply of water to each heat exchanger. In one aspect of the invention, the main and secondary heat exchangers are connected in series. Alternatively, the main and secondary heat exchangers may be connected in parallel. Advantageously, the vent assembly comprises a shaft engaging means for engaging in the vent shaft. In one aspect of the invention, the vent assembly comprises a housing which forms the main duct, and the shaft engaging means. In another aspect of the invention, an outlet cover engagable with the housing adjacent the downstream end of the main duct is provided, the outlet cover forming the secondary duct outlet, and the main duct outlet communicating with the secondary duct outlet for delivering air from the main duct to the room. Preferably, the outlet cover is releasably engagable with the housing. Advantageously, the secondary duct inlet is formed in the outlet cover. In one aspect of the invention, the outlet cover forms with the housing the secondary duct. In another aspect of the invention, an access opening is provided through the outlet cover for providing access to the valve means. Preferably, a closure member releasably closes the access opening. Advantageously, the closure member is hingedly connected to the outlet cover and is hingable from an open position exposing the access opening to a closed position closing the access opening. Preferably, the secondary duct outlet and the secondary duct inlet are formed by louvre outlets. In one embodiment of the invention, the housing comprises a pair of spaced apart side walls joined by spaced apart outer top and bottom walls for extending into the vent shaft, and an inner top wall and an inner bottom wall extending between the side walls for forming with the side walls the main duct, the inner top wall and outer bottom wall with the respective side walls defining the main duct inlet, and the inner bottom wall with the outer top wall and the respective side walls defining the main duct outlet. Advantageously, the inner top wall inclines downwardly from the outer top wall towards the main duct inlet, and preferably, the inner bottom wall inclines upwardly from the outer bottom wall towards the main duct outlet. Ideally, the inner and outer top walls form an enclosed heat insulating cavity. In one aspect of the invention, the shaft engaging means comprises a tubular shaft liner for engaging and lining the vent shaft, the shaft liner extending between a liner inlet and a liner outlet for, in use, coinciding with the shaft inlet and the shaft outlet, respectively, the main duct extending into the shaft liner. Preferably, the shaft liner comprises a pair of elongated telescoping members, one of said telescoping members being slidable within the other for accommodating wall vents of differing length. In another aspect of the invention, an air filter is located in the shaft liner adjacent the liner inlet, for filtering air passing through the main duct. In a further aspect of the invention, an inlet cover is engagable with the shaft liner adjacent the liner inlet, the inlet cover having an air inlet which communicates with the main duct inlet, and preferably, the inlet cover is releasably engagable with the shaft liner. Ideally, a securing means is provided for releasably securing the inlet cover to the shaft liner, and preferably, the securing means is operable by an operating means adjacent the liner outlet. It is preferable that the housing is located in the shaft liner with the main duct outlet substantially adjacent the liner outlet and the main duct inlet being located towards the liner inlet. Additionally, the invention provides a wall having a wall vent extending therethrough and the vent assembly according to the invention located therein. Preferably, the wall vent is located in the wall towards the floor of the room. Additionally, the invention provides a method for heating air entering a room through a wall vent, the wall vent being of the type comprising a vent shaft extending through the wall from a shaft inlet formed in an outer surface of the wall to a shaft outlet formed in an inner surface thereof adjacent the room, wherein the method comprises the step of placing a main heating means in the wall vent for heating the air passing therethrough. Preferably, the method includes the step of placing the main heating means intermediate the shaft inlet and the shaft outlet. Advantageously, the main heating means is located in the vent shaft at a level intermediate the shaft inlet and the shaft outlet. Ideally, the main heating means is located in the vent shaft at a level below the shaft outlet and above the shaft inlet. In one embodiment of the invention, the main heating means comprises a main water heat exchanger. The invention will be more clearly understood from the following description of a preferred embodiment thereof which is given by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a vent assembly according to the invention, Fig. 2 is a typical cross sectional side elevational view of the vent assembly of Fig. 1 illustrated located in a wall vent, Fig. 3 is a rear end elevational view of the wall vent of Fig. 1, Fig. 4 is a front end elevational view of the wall vent of Fig. 1, with portion of the wall vent in a different position, Fig. 5 is a rear end elevational view of the vent assembly of Fig. 1 with portion of the vent assembly removed, Fig. 6 is a rear end elevational view of the vent assembly of Fig. 1 with a further portion of the vent assembly removed, Fig. 7 is a cross sectional end elevational view of the vent assembly of Fig. 1 on the line VII-VII of Fig. 2, Fig. 8 is a perspective view of portion of the vent assembly of Fig. 1, Fig. 9 is an exploded perspective view of part of the portion of Fig. 8, Fig. 10 is a perspective view of part of the vent assembly of Fig. 1, Fig. 11 is a perspective view of another part of the vent assembly of Fig. 1, Fig. 12 is a perspective view of a detail of the vent assembly of Fig. 1, and Fig. 13 is a partly cut-away perspective view of the vent assembly of Fig. 1 mounted in a wall. Referring to the drawings there is illustrated a vent assembly according to the invention indicated generally by reference numeral 1 for mounting in a wall vent 2 of a wall 3 of a room of a house, building or the like for heating air entering the room through the wall vent 2. Before describing the vent assembly in detail, the wall 3 and wall vent 2 will first be described. The wall 3 is an outer wall of the room and is constructed with insulated cavity blocks 5 which form an outer surface 6 of the wall 3, in other words, the outside surface of the wall 3. The wall 3 is dry lined with a studded dry liner 7 which defines an inner surface 8 of the wall 3, in other words, the room surface of the wall 3. The wall vent 2 is located relatively low in the wall 3, just above floor level above a skirting board 9. The wall vent 2 is provided by a horizontal vent shaft 10 of rectangular cross-section which extends through the wall 3 from a shaft inlet 14 formed in the outer surface 6 of the wall 3 to a shaft outlet 15 formed in the inner surface 8 of the wall 3 for delivering air into the room from outside. The vent assembly comprises a housing 17 which is located in the vent shaft 10 in a shaft engaging means provided by an elongated tubular shaft liner 18. The shaft liner 18 extends through the vent shaft 10 from the shaft inlet 14 to the shaft outlet 15 for accommodating air through the vent shaft 10. The housing 17 which is described in detail below forms an elongated main duct 20 for accommodating the air through the shaft liner 18 into the room. The main duct 20 extends from a main duct inlet 21 at an upstream end 22 which communicates with and receives air from the shaft inlet 14 to a main duct outlet 23 at a downstream end 24 which is located adjacent the shaft outlet 15 for delivering air into the room. A main heating means, namely, a main water heat exchanger 25 is located in the main duct 20 intermediate the main duct inlet 21 and the main duct outlet 23 for heating air passing through the main duct 20 into the room. The shaft liner 18 comprises a pair of telescoping liner members, namely, an inner liner member 29 which is slidable within an outer liner member 30, both of injection moulded plastics material. The inner liner member 29 extends inwardly into the vent shaft 10 from the shaft inlet 14, and an inlet mounting flange 31 extending completely around the inner liner member 29 defines a liner inlet 28 and engages the wall 3 around the shaft inlet 14. The outer liner member 30 extends inwardly into the vent shaft 10 from the shaft outlet 15 and terminates in an outlet mounting flange 32 which extends completely around the outer liner member 30 for abutting the wall 3 adjacent the shaft outlet 15. The outlet mounting flange 32 defines a liner outlet 33 from the shaft liner 18. In practice, grouting would be provided around the shaft liner 18 between the shaft liner 18 and the wall 3. A plurality of anchor blocks 34 integrally injection moulded with the respective liner members 29 and 30 are provided around the inner and outer liner members 29 and 30 extending from the respective mounting flanges 31 and 32. Bores (not shown) which may or may not be tapped extend into the anchor blocks 34 from the outlet mounting flange 32 for receiving screws 36 or self tapping screws for securing the vent assembly 1 as will be described below in the shaft liner 18. Bores (not shown) also extend into the anchor blocks 34 from the inlet mounting flange 31 for receiving screws 37 for securing another component to the shaft liner 18 as will be described below. The housing 17 is of injection moulded plastics material and comprises a pair of spaced apart side walls 38 and 39 which are joined by an outer top wall 40 and an outer bottom wall 41. An upstream locating flange 43 extends outwardly of the side walls 38 and 39 and the top and bottom walls 40 and 41 and extends completely around the housing 17 for engaging the inner liner member 29 for locating the housing 17 centrally in the shaft liner 18. A mounting flange 45 extends around the housing 17 at the downstream end 24 and extends outwardly of the side walls 38 and 39 and top and bottom walls 40 and 41 for mounting and securing the housing 17 to the shaft liner 18. Holes 46 through the mounting flange 45 accommodate the screws 36 for securing the mounting flange 45 to the outlet mounting flange 32 of the shaft liner 18. A downstream locating flange 47 similar to the upstream locating flange 43 also extends completely around the housing 17 for locating the housing 17 in the shaft liner 18 at the downstream end 24. An inner top wall 49 extending between the side walls 38 and 39 extends and inclines generally downwardly from the outer top wall 40 adjacent the main duct outlet 23 towards the main duct inlet 21. An inner bottom wall 50 extending between the side walls 38 and 39 extends and is inclined upwardly from the outer bottom wall 41 towards the main duct outlet 23. The inner top wall 49 and the inner bottom wall 50 together with the side walls 38 and 39 and part of the outer bottom wall 41 form the main duct 20. An intermediate portion 51 of the main duct 20 extends in a generally vertical direction, and accordingly, the main duct inlet 21 is at a level below the level of the main duct outlet 23 to facilitate flow of air through the main duct 20 by natural convection, as the air is heated by the main heat exchanger 25. Mounting grooves 52 and 53 are provided in the inner top wall 49 and the inner bottom wall 50, respectively, adjacent the intermediate vertical portion 51 of the main duct 20 for mounting the main heat exchanger 25. An upstream end wall 54 forms with the side walls 38 and 39 and the outer top wall 40 and inner top wall 49 a heat insulating cavity 55 which is air filled to act as a heat insulator between the main duct 20 and the shaft liner 18. An area 56 formed between the side walls 38 and 39 and the outer bottom wall 41 and the inner bottom wall 50 is open at the downstream end 24 for accommodating components of the main heat exchanger 25 as will be described below. The housing 17 is formed in two parts as is illustrated in Fig. 9, one part comprises the side wall 39, and the other part forms the remainder of the main housing 17. Locating protrusions 56 and 57 extend from the side wall 39 for engaging the cavity 55 and the area 56 for locating and aligning the side wall 39 with the remainder of the housing 17. Screws 60 through holes 61 engage tapped bores 62 in the remaining portion of the housing 17 for securing the side wall 39 to the remaining portion of the housing 17. The main heat exchanger 25 is provided by a radiator which comprises a plurality of elongated parallel spaced apart water carrying tubes 65 which are connected in series from a water inlet 66 to a water outlet 67. The tube 65 define an outer heat exchange surface 68 for transferring heat to the air passing through the main duct 20. A plurality of parallel spaced apart heat exchange fins 69 engage the tubes 65 with heat conducting engagement for transferring heat to the air passing through the main duct 20. The fins 69 extend transversely of the main duct 20 between the side walls 38 and 39. Mounting brackets 70 and 71 at opposite ends of the tubes 65 engage the mounting grooves 52 and 53, respectively, for locating and retaining the main heat exchanger 25 in the intermediate vertical portion 51 of the main duct 20. The tubes 65, and accordingly, the main plane of the main heat exchanger 25 extend substantially horizontally across the intermediate vertical portion 51 of the main duct 20. The main heat exchanger 25 is mounted in the duct 20 so that all air passing through the main duct 20 passes through the heat exchanger 25. An accommodating means, namely, an accommodating opening 72 and 73 through the outer bottom wall 41 and inner bottom wall 50, respectively, accommodate a flow and a return pipe 74 and 75 from a cental heating system for connecting to the water inlet 66 and a water outlet 67 of the main heat exchanger 25. The flow pipe 74 is connected to the water inlet 66 through a hand operated valve 76 for controlling the flow of water to the main heat exchanger 25. The hand operated valve 76 is partly located in the area 56 formed between the outer bottom wall 41 and inner bottom wall 50. An outlet cover 78 of injection moulded plastics material is located at the downstream end 24 of the main duct 20 and is secured to the housing 17. The outlet cover 78 comprises a front wall 79 and a pair of side walls 80a and b extending from the front wall 79 to the housing 17. A top wall 81 extends between the side walls 80 from the front wall 79 to the housing 17. A downwardly extending flange 83 from the top wall 81 engages behind a corresponding flange 84 extending upwardly from the mounting flange 45. Screws (not shown) through mounting brackets (also not shown) on the side walls 80 secure the outlet cover 78 to the mounting flange 45. An air outlet 88 is provided by a louvred opening in the upper half of the front wall 79 and communicates with the main duct outlet 23 for delivering warm air from the main duct 20 into the room. An outwardly upwardly directed lip 89 extends from the inner bottom wall 50 for directing air from the main duct 20 towards the outlet 88. The front wall 79 of the outlet cover 78 is spaced apart from the main housing 17 and a portion 77 of the front wall 79 with the side wall 80a and an intermediate side wall 87 forms with the main housing 17 a secondary duct 90. The intermediate side wall 87 extends inwardly from the portion 77 of the front wall 79 at 57 to the main housing 17, and the intermediate side wall 87 extends downwardly from a position just below the air outlet 88. A secondary heating means, namely, a secondary heat exchanger 91 is located in the secondary duct 90 for heating air passing through the secondary duct 90. The secondary heat exchanger 91 is provided by a radiator and is substantially similar to the main heat exchanger 25, and comprises a plurality of parallel spaced apart water carrying heat exchange tubes 94 and transversely extending heat exchange fins 95. Mounting brackets 85 at opposite ends of the tubes 94 are secured to the inner bottom wall 50 by screws 86 for securing the secondary heat exchanger 91 in the secondary duct 90. The secondary heat exchanger 91 extends transversely and completely across the secondary duct 90 from the side wall 80a to the intermediate side wall 87. A water inlet 96 and a water outlet 97 of the secondary heat exchanger 91 are connected to the flow and return pipe 74 and 75. The water inlet 96 is connected through a hand operated valve 98 for controlling and regulating the flow of water to the secondary heat exchanger 91. An access opening 99 to the hand operated valves 76 and 98 is provided in the front wall 79 of the outlet cover 78, and a closure means, namely, a closure member 100 hingedly connected to the outlet cover 78 at 101 closes the access opening 99. A clasp (not shown) is provided on the closure member 100 for securing the closure member 100 in the outlet cover 78 in the closed position. A secondary air inlet 92 to the secondary duct 90 is formed by a plurality of inlet slots 93 in a bottom wall 82 of the closure member 100 for communicating the secondary duct 90 with the room. The secondary duct 90 extends upwardly from the inlet slots 93 to the outlet 88 in the outlet cover 78 which forms a secondary outlet from the secondary duct 90 so that air from the room can circulate through the secondary duct 90 for heating by the secondary heat exchanger 91 from the secondary inlet 92 through the outlet 88. An inlet cover 105 is secured to the shaft liner 18 at the liner inlet 28. The inlet cover 105 comprises a downwardly extending flange 106 which engages behind the inlet mounting flange 31, and a lower flange 107 at the lower end of the inlet cover 105 abuts and engages a lower portion of the inlet mounting flange 31. A securing means, namely, a latch 108 carried on an operating means, namely, an operating bar 109 releasably secures the inlet cover to the shaft liner 18. The operating bar 109 is rotatably mounted in the shaft liner 18, and the latch 109 releasably engages a corresponding receiver recess 110 in the lower flange 107 of the inlet cover 105. The bar 105 is rotatably carried in bores (not shown) in the inlet mounting flange 31 and the outlet mounting flange 32 of the shaft liner 18. A lever 114 adjacent the outlet mounting flange 32 provides for operation of the latch 108 from the room. An air inlet 116 provided by a louvred opening in the inlet cover 105 communicates the main duct inlet 21 with the outside air so that air can be drawn from the outside of the house through the main duct 20. An air filter comprising a panel filter 117 is carried in a frame 118 and is secured and located in a recess 119 which extends completely around the inlet mounting flange 31 of the shaft liner 18 for filtering air passing into the main duct 20. The screws 37 secure the air filter 117 to the inlet mounting flange 31. The housing 17, the shaft liner 18 and the inlet and outlet covers 105 and 78, respectively, may be of any desired plastics material, but are preferably of a heat stable plastics material which would be stable at temperatures up to 100°C, such as for example, nylon, polypropylene or polycarbonate. In this embodiment of the invention the mean heat output capacity of the main heat exchanger 25 is 850 watts approximately and the mean heat output capacity of the secondary heat exchanger 91 is 200 watts approximately. The heat output value for the main heat exchanger is based on an air flow rate of 50 M 3 per hour through the main heat exchanger 25 with an inlet air temperature of 9.5°C and an outlet air temperature of 61.7°C with a water-on temperature of 64°C. The heat output value of the secondary heat exchanger 91 is based on an air flow rate of 25 M 3 per hour, with an inlet air temperature of 16°C and an outlet air temperature of 41.3°C for a water-on temperature of 63°C. Needless to say, the heat output values will vary depending on air flow rate over the heat exchangers, water temperature, and indeed water flow rates through the heat exchangers. The internal cross-sectional dimension of the shaft liner 18 are 220 mm high by 226 mm wide. The length of the shaft liner 18 is approximately 290 mm, however, this latter dimension may vary depending on the thickness of the wall 3, which will be determined by the type of the wall in which the vent assembly is being located. The transverse dimensions of the main duct inlet at its narrowest point are 50 mm high by 200 mm wide and the transverse cross-section dimensions of the main duct outlet at its narrowest point are 72 mm high by 200 mm wide. The transverse cross-sectional dimension of the duct at the intermediate vertical portion 51 are approximately 165 mm by 200 mm. Thus, giving a transverse cross-sectional area at the intermediate vertical portion of the main duct of 33,000 mm 2 . Thus, the transverse cross-sectional area of the duct taken up by the main heat exchanger 25 is 33,000 mm 2 . In use, if a wall vent 2 is already provided in the wall, the wall vent is lined by inserting the inner liner member 29 and the outer liner member 30 of the shaft liner 18 into the wall vent 2 so that the inlet mounting flange 31 and the outlet mounting flange 32 abuts the wall surfaces adjacent the shaft inlet 14 and the shaft outlet 15, respectively. On the other hand, if a wall vent is not already provided, a wall vent 2 must first be formed through the wall 3. It is recommended that the wall vent should be located as low as possible in the wall 3 towards floor level, and preferably, just above the skirting board 9 to obtain maximum advantage from the vent assembly, in other words, to provide for maximum circulation of the warm air from the vent assembly 1 throughout the room. A typical ideal location for the wall vent 2 and vent assembly 1 is illustrated in Fig. 13. With the vent shaft 10 of the wall vent 2 lined with the shaft liner 18, the housing 17 is then entered through the shaft liner 18 from the liner outlet 33 and is secured in the shaft liner 18 by the screws 36 engaging the anchor blocks 34 through the mounting flange 45. The flow and return pipes 74 and 75 are connected to corresponding flow and return pipes from the central heating system. Typically, the flow and return pipes of the central heating system would be fed through a cavity 120 between the cavity blocks 5 and the dry liner 7 , see Fig. 2. The outlet cover 78 is then secured to the mounting flanger 45 of the housing 17. The air filter 117 is located and secured in the inlet mounting flange 31 of the shaft liner 18, and the inlet cover 105 is also engaged on the inlet mounting flange 31. The latch 108 is operated by the lever 114 for securing the inlet cover 105 to the shaft liner 18. The supply of water to the main and secondary heat exchangers 25 and 91 is controlled and regulated by the valves 76 and 98, respectively. Access to the valves 76 and 98 is gained by hinging the closure member 100 downwardly into the open position as illustrated in Fig. 13. On the desired flow of water through the heat exchangers 25 and 91 being achieved the closure member 100 is closed. Where the vent assembly 1 is mounted in a wall vent 2 of a room where there is a natural draught, for example, from a gas powered or oil powered boiler, or a solid fuel powered boiler, air is drawn into the room through the vent assembly 1 and heated as the air passes through the main heat exchanger 25. The warm air is thus delivered into the room through the outlet 88 in the outlet cover 78 and is circulated through the room. Additional heating and circulation of air is achieved by the secondary heat exchanger 91. Air through natural convection passes through the secondary duct 90 and is heated by the secondary heat exchanger 91 and in turn delivered back to the room through the outlet 88 in the outlet cover 78. Where the vent assembly 1 is mounted in a wall vent 2 where a room is not subjected to a draught, natural convection of air will take place through the main duct 20 which is delivered into the room through the outlet 88 in the outlet cover 78. This natural convection takes place by virtue of the fact that the main duct 20 is inclined upwardly from the main duct inlet 21 to the main duct outlet 23. Thus, the heating action of the main heat exchanger 25 on the air in the main duct 20 causes the air in the main duct 20 to pass through the main duct 20 into a room by natural convection. Natural convection also takes place through the secondary duct. Additionally, by virtue of the relative positions of the main duct 20 and the secondary duct 90, in other words, the fact that the secondary duct 90 joins the main duct at the air outlet 88, it is believed that a venturi effect will be caused by air flowing through the main duct 20, and the air flowing through the main duct 20 will tend to draw air through the secondary duct 90. It is believed that the provision of the lip 89 extending from the inner bottom wall 50 towards the air outlet 88 in the outlet cover 78 will enhance the venturi effect of the air flowing through the main duct 20 on air passing through the secondary duct 90. While the vent assembly has been described as being provided in a wall vent relatively close to the floor, the vent assembly may be located in a wall vent in any other desired location or wall, and in certain cases may be located in a wall vent adjacent a ceiling of a room. It is also envisaged that while the vent assembly has been described for mounting in a wall vent of an outside wall of a house, the vent assembly may be mounted in a wall vent in any wall whether it be an internal wall or an external wall. In cases where the vent assembly is mounted in an internal wall, for example, a wall adjoining another room which is adjacent the room in which the boiler is located, it is envisaged that a second vent assembly may be provided in the exterior wall of the adjoining room so that air will be drawn by the boiler, first through the external wall into the adjoining room, and then from the adjoining room through the vent assembly in the internal wall into the room in which the boiler is located. In which case, air will be heated as it passes through both vent assemblies, thus heating the air entering the adjoining room through the vent assembly in the external wall, and also further heating the air passing through the vent assembly in the internal wall as it enters the room in which the boiler is located. Indeed, it is envisaged that a sequence of vent assemblies may be provided to heat two or more rooms in this fashion. Additionally, it will be appreciated that the vent assembly may be located in a wall of any type of a building, for example, an office building, a commercial building, factory or the like. While the vent assembly has been described as being provided with a secondary duct and a secondary heat exchanger, in certain cases, if desired these may be omitted. It will of course be appreciated that where a secondary heating means is provided, any other suitable type of heating means may be provided besides a water heat exchanger. Additionally, it may be appreciated that the main heating means may be provided by a heating exchange means other than a water heat exchanger. Indeed, in certain cases, it is envisaged that the main heating means may be provided by an electrically powered heater. It will also be appreciated that while it is preferable, it is not essential that main heating means be located within the main duct, the main heating means may be located outside the main duct, for example, around the main duct to heat the duct to, in turn, heat air passing through the duct. While it is preferable, it is not essential that the main duct should be inclined upwardly from the main duct inlet to the main duct outlet. Needless to say, it is appreciated that the housing which forms the main duct may be of other construction than that described. It will of course be appreciated that while it is preferable to locate the housing in a shaft liner, in certain cases, it is envisaged that the housing may be mounted directly in the vent shaft. It is also envisaged that a fan or other air circulating means may be provided in the main duct, and indeed, in the secondary duct where such a duct is provided for further assisting delivery of air through the respective ducts. Such a fan or fans may be driven by an electrically powered motor, or by any other suitable drive means. Needless to say, the vent assembly may be located in a wall for delivering air into a room where there is no dependence on a draught created by a boiler. In which case, a fan may be provided in the main duct for assisting air flow through the main duct, or alternatively, natural convection through the main duct may be relied on. While the vent assembly has been described as being located completely in the vent shaft, in certain cases, it is envisaged that only portion of the vent assembly would be located within the vent shaft, the remainder of the vent assembly would be located exteriorly of the vent shaft, and may be located on the exterior of the wall or on the interior thereof. It is also envisaged that in certain cases the vent shaft may be horizontal or inclined to the horizontal, and preferably, where the vent shaft is inclined, the vent shaft would rise from the shaft inlet to the shaft outlet. While the vent assembly has been described as being manufactured from injection moulded plastics materials, the vent assembly may be manufactured using any other technique for forming the plastics material. Needless to say, the vent assembly may be of any other material besides plastics material, for example, metal, sheet metal, cast metal, concrete or any other suitable cementitious material, wood, reconstituted wood, or indeed, any combination of the above materials. It is also envisaged that part of the fence assembly may be manufactured of one material while another part may be of another material. For example, it is envisaged that the shaft liner may be formed of sheet metal, while the main housing may be formed of plastics material. While the main and secondary heat exchangers have been described as being connected in parallel to the flow and return pipe of a central heating system, it will be readily appreciated that the main and secondary heat exchangers may be connected in series to the flow and return pipe of a central heating system. In which case, a single valve would be sufficient. Needless to say, if desired, the valves may be omitted. Additionally, it will be appreciated that other accommodating means besides the accommodating slots in the outer bottom wall and the inner bottom wall for accommodating flow and return pipes to the main and secondary heat exchangers may be provided. For example, accommodating openings, slots or grooves may be formed in any other suitable part of the main housing, or indeed, in certain cases through the outlet cover.

Claims: CLAIMS 1. A vent assembly for mounting in a wall vent (2) extending through a wall (3) of a room, the wall vent (2) being of the type having a vent shaft (10) extending through the wall (3) from a shaft inlet (14) formed in the outer surface (6) of the wall to a shaft outlet (15) formed in the inner surface (8) of the wall (3), the vent assembly (1) being of the type comprising an elongated main duct (20) for mounting in the vent shaft (10) for delivering air through the vent shaft (10) into the room, the main duct (20) extending between a main duct inlet (21) at an upstream end (22) for receiving the air, and a main duct outlet (23) at a downstream end (24) through which the air is delivered to the room, characterised in that a main heating means (25) for heating air flowing through the main duct (20) is provided. 2. A vent assembly as claimed in Claim 1 characterised in that the main heating means (25) is located in the main duct (20). 3. A vent assembly as claimed in Claim 1 or 2 in which the main heating means (25) extends transversely of the main duct (20). 4. A vent assembly as claimed in Claim 3 characterised in that the main heating means (25) extends completely across the main duct (20) so that substantially all the air passing through the main duct (20) passes through the main heating means (25). 5. A vent assembly as claimed in any preceding claim characterised in that the main duct (20) rises from the main duct inlet (21) to the main duct outlet (23). 6. A vent assembly as claimed in any preceding claim characterised in that the main duct inlet (21) is below the level of the main duct outlet (23). 7. A vent assembly as claimed in any preceding claim characterised in that the main heating means (25) extends in a plane substantially horizontally. 8. A vent assembly as claimed in any preceding claim characterised in that the main heating means (25) is located at a level below the main duct outlet (23) and at a level above the main duct inlet (21). 9. A vent assembly as claimed in any preceding claim in which an intermediate portion (51) of the main duct (20) intermediate the upstream end (22) and the downstream end (24) extends in a substantially vertical direction, the main heating means (25) being located in the vertically extending intermediate portion (51) of the main duct (20). 10. A vent assembly as claimed in any preceding claim characterised in that the main heating means (25) comprises a main water heat exchanger (25). 11. A vent assembly as claimed in Claim 10 characterised in that the main water heat exchanger (25) comprises a radiator comprising a plurality of spaced apart elongated water carrying heat exchange tubes (65) defining respective outer heat exchange surfaces (68) for transferring heat from the water to air. 12. A vent assembly as claimed in Claim 11 characterised in that a plurality of spaced apart heat exchange fins (69) extend from the heat exchange tubes (65) of the main heat exchanger (25), the heat exchange fins (69) engaging the heat exchange tubes (65) with heat conducting engagement for transferring heat to the air. 13. A vent assembly as claimed in any preceding claim characterised in that a secondary duct (90) is provided extending from a secondary duct outlet (88) adjacent the main duct outlet (23) to a secondary duct inlet (92) for receiving air from the room for delivering the air through the secondary duct (90) and through the secondary duct outlet (88) for return to the room. 14. A vent assembly as claimed in Claim 13 characterised in that a secondary heating means (91) is provided for heating air flowing through the secondary duct (90). 15. A vent assembly as claimed in Claim 14 characterised in that the secondary heating means (91) is located in the secondary duct (90). 16. A vent assembly as claimed in Claim 14 or 15 characterised in that the secondary heating means (91) extends transversely across the secondary duct (90). 17. A vent assembly as claimed in any of Claims 14 to 16 characterised in that the secondary heating means (91) extends completely across the secondary duct (90). 18. A vent assembly as claimed in any of Claims 14 to 17 characterised in that the secondary duct (90) rises from the secondary duct inlet (92) towards the secondary duct outlet (88). 19. A vent assembly as claimed in any of Claims 13 to 18 characterised in that the secondary duct outlet (88) is above the level of the secondary duct inlet (92). 20. A vent assembly as claimed in any of Claims 13 to 19 characterised in that the secondary heating means (91) is located below the secondary duct outlet (88) and above the secondary duct inlet (92). 21. A vent assembly as claimed in any of Claims 13 to 20 characterised in that the secondary heating means (91) comprises a secondary water heat exchanger (91). 22. A vent assembly as claimed in Claim 21 characterised in that the secondary water heat exchanger (91) comprises a radiator comprising a plurality of spaced apart elongated water carrying heat exchange tubes (94) defining respective outer heat exchange surfaces for transferring heat from the water to air. 23. A vent assembly as claimed in Claim 22 characterised in that a plurality of spaced apart heat exchange fins (95) extend from the heat exchange tubes (94) of the secondary heat exchanger, the heat exchange fins (95) engaging the heat exchange tubes (94) with heat conducting engagement for transferring heat to the air. 24. A vent assembly as claimed in any of Claims 14 to 23 characterised in that an accommodating means (72,73) is provided for accommodating a flow and return pipe for connection to each heat exchanger (25,91). 25. A vent assembly as claimed in any of Claims 14 to 23 characterised in that a valve means (76,98) is provided for controlling the supply of water to each heat exchanger (25,91). 26. A vent assembly as claimed in any of Claims 14 to 25 characterised in that the main and secondary heat exchangers (25,91) are connected in series. 27. A vent assembly as claimed in any of Claims 14 to 25 characterised in that the main and secondary heat exchangers (25,91) are connected in parallel. 28. A vent assembly as claimed in any preceding claim characterised in that the vent assembly (1) comprises a shaft engaging means (18) for engaging in the vent shaft (10). 29. A vent assembly as claimed in Claim 28 characterised in that the vent assembly (1) comprises a housing (17) which forms the main duct (20), and the shaft engaging means (18). 30. A vent assembly as claimed in Claim 29 characterised in that an outlet cover (78) engagable with the housing (17) adjacent the downstream end (24) of the main duct (20) is provided, the outlet cover (78) forming the secondary duct outlet (88), and the main duct outlet (23) communicating with the secondary duct outlet (88) for delivering air from the main duct (20) to the room. 31. A vent assembly as claimed in Claim 30 characterised in that the outlet cover (78) is releasably engagable with the housing (17). 32. A vent assembly as claimed in Claim 30 or 31 characterised in that the secondary duct inlet (92) is formed in the outlet cover (78). 33. A vent assembly as claimed in any of Claims 30 to 32 characterised in that the outlet cover (78) forms with the housing (17) the secondary duct (90). 34. A vent assembly as claimed in any of Claims 30 to 33 characterised in that an access opening (99) is provided through the outlet cover (78) for providing access to the valve means (76,98). 35. A vent assembly as claimed in Claim 34 characterised in that a closure member (100) releasably closes the access opening (99). 36. A vent assembly as claimed in Claim 35 characterised in that the closure member (100) is hingedly connected to the outlet cover (78) and is hingable from an open position exposing the access opening (99) to a closed position closing the access opening (99). 37. A vent assembly as claimed in any of Claims 30 to 36 characterised in that the secondary duct outlet (88) and the secondary duct inlet (92) are formed by louvre outlets. 38. A vent assembly as claimed in any of Claims 29 to 37 characterised in that the housing (17) comprises a pair of spaced apart side walls (38,39) joined by spaced apart outer top and bottom walls (40,41) for extending into the vent shaft (10), and an inner top wall (49) and an inner bottom wall (50) extending between the side walls (38,39) for forming with the side walls (38,39) the main duct (20), the inner top wall (49) and outer bottom wall (41) with the respective side walls (38,39) defining the main duct inlet (21), and the inner bottom wall (50) with the outer top wall (40) and the respective side walls (38,39) defining the main duct outlet (23). 39. A vent assembly as claimed in Claim 38 characterised in that the inner top wall (49) inclines downwardly from the outer top wall (40) towards the main duct inlet (21). 40. A vent assembly as claimed in Claim 38 or 39 characterised in that the inner bottom wall (50) inclines upwardly from the outer bottom wall (41) towards the main duct outlet (23). 41. A vent assembly as claimed in any of Claims 38 to 40 characterised in that the inner and outer top walls (49,40) form an enclosed heat insulating cavity (55). 42. A vent assembly as claimed in any preceding claim characterised in that the shaft engaging means (18) comprises a tubular shaft liner (18) for engaging and lining the vent shaft (10), the shaft liner (18) extending between a liner inlet (28) and a liner outlet (33) for, in use, coinciding with the shaft inlet (14) and the shaft outlet (15), respectively, the main duct (20) extending into the shaft liner (18). 43. A vent assembly as claimed in Claim 42 characterised in that the shaft liner (18) comprises a pair of elongated telescoping members (29,30), one of said telescoping members (29) being slidable within the other (30) for accommodating wall vents (2) of differing length. 44. A vent assembly as claimed in Claim 42 or 43 characterised in that an air filter (117) is located in the shaft liner (18) adjacent the liner inlet (28). 45. A vent assembly as claimed in any of Claims 42 to 44 characterised in that an inlet cover (105) is engagable with the shaft liner (18) adjacent the liner inlet (28), the inlet cover (105) having an air inlet (116) which communicates with the main duct inlet (21). 46. A vent assembly as claimed in Claim 45 characterised in that the inlet cover (105) is releasably engagable with the shaft liner (18). 47. A vent assembly as claimed in Claim 45 or 46 characterised in that a securing means (108,110) is provided for releasably securing the inlet cover (105) to the shaft liner (18). 48. A vent assembly as claimed in Claim 47 characterised in that the securing means (108) is operable by an operating means (109,114) adjacent the liner outlet (33). 49. A vent assembly as claimed in any of Claims 42 to 48 characterised in that the housing (17) is located in the shaft liner (18) with the main duct outlet (23) substantially adjacent the liner outlet (33) and the main duct inlet (21) being located towards the liner inlet (28). 50. A wall (3) having a wall vent (2) extending therethrough and the vent assembly (1) as claimed in any preceding claim located therein. 51. A wall as claimed in Claim 50 characterised in that the wall vent (2) is located in the wall (3) towards the floor of the room. 52. A method for heating air entering a room through a wall vent (2), the wall vent (2) being of the type comprising a vent shaft (10) extending through the wall (3) from a shaft inlet (14) formed in an outer surface (6) of the wall (3) to a shaft outlet (15) formed in an inner surface (8) thereof adjacent the room, characterised in that the method comprises the step of placing a main heating means (25) in the wall vent (2) for heating the air passing therethrough. 53. A method as claimed in Claim 52 characterised in that the main heating means (25) is placed in the vent shaft (10) in the path of the air. 54. A method as claimed in Claim 52 or 53 characterised in that the method includes the step of placing the main heating means (25) intermediate the shaft inlet (14) and the shaft outlet (15). 55. A method as claimed in any of Claims 52 to 54 characterised in that the main heating means (25) is located in the vent shaft (10) at a level intermediate the shaft inlet (14) and the shaft outlet (15). 56. A method as claimed in any of Claims 52 to 55 characterised in that the main heating means (25) is located in the vent shaft (10) at a level below the shaft outlet (15) and above the shaft inlet (14). 57. A method as claimed in any of Claims 52 to 56 characterised in that the main heating means (25) comprises a main water heat exchanger (25).

Inventors: HANLON JOHN FRANCIS, HANLON, JOHN, FRANCIS
Applicants: HA HA CO LTD, HANLON JOHN FRANCIS, HANLON, JOHN, FRANCIS, THE HA HA COMPANY LIMITED
Application year: 1994
Main classification: F24D19
IPC codes: F24D19